周期加筋板中的弯曲波传播

本文采用波动分析法分析了周期加筋板中的弯曲波传播，推导了周期加筋板的波传播方程，分析了振动频率和平面弯曲波入射角对传播常数的影响。研究表明：平面弯工波以某一角度入射周期加筋板时，随着频率的变化，会交错的出现弯曲波传递的穿透频段和阻塞频段；周期加筋板没有明显的穿透频段。本文的研究为周期加筋板应用于结构声传递途径的控制提供了理论基础。     

多因素耦合作用下混凝土氯盐侵蚀模糊网络评估模型

单位时间内通过混凝土结构的总电荷量是反映混凝土结构氯离子渗透能力的一个重要指标。针对传统经验公式法预测了氯离子总电荷量的不足,建立了一个模糊-神经网络模型以预测氯离子总电荷量。此模型能同时考虑多种因素及其非线性耦合作用,方便易行、通用性好,较之其它神经网络具有运算速度快、不容易陷入局部最优、训练效果好的特点。训练样本训练后的结果表明,该模型具有较高的准确度,能可靠预测氯离子总电荷量,准确评价混凝土结构的抗氯盐侵蚀能力,为实际工程的耐久性设计和评价提供依据。     

Age differences in attitude change: Influences of cognitive resources and motivation on responses to argument quantity.

This study examined the influences of cognitive resources and motivation on how young and older adults process different quantities of persuasive arguments. In the first experiment session, both young and older adults rated their attitudes toward marijuana legalization and capital punishment. After a week, they read either 3 or 9 similar-quality arguments supporting marijuana legalization and capital punishment. Half of participants were assigned to the high-involvement condition (i.e., told that they were going to discuss the arguments later with the experimenter) and the other half were assigned to the low-involvement condition (i.e., given no instructions). After reading the arguments, participants rated their attitudes toward those 2 social issues again. Highly involved young adults changed their attitudes regardless of the quantity of arguments, whereas lowly involved young adults' attitude change was influenced by the argument quantity. Older adults in both high-involvement and low-involvement conditions changed their attitudes according to the argument quantity. Working memory was found to mediate the age effects on attitude change. This finding demonstrated the importance of a cognitive mechanism in accounting for age differences in attitude change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

一种基于辩论的决策方法研究

为了解决动态开放环境下决策方案可行性论证的难题,将辩论理论与实用推理结合提出了一种新的适用于多属性决策的辩论框架,定义了论据的类型和论据之间可能存在的攻击关系。将基于辩论的多属性决策过程分为用户需求获取、方案可行性论证和可行方案选优3个阶段,通过论据及其攻击关系对方案的可行性进行辩论论证。最后采用一个医疗决策问题对该框架的应用进行了示例说明,结果表明,该框架能够较好的处理信息不完整、不一致条件下的决策问题。     

三门峡水电站水轮机过流部件防护材料的筛选及防护方案

水轮机过流部件表面防护材料筛选试验及防护方案的确定是三门峡水电站汛期浑水发电试验的一项重要内容。通过近４０种抗磨材料的筛选试验，确定了如下的防护方案：①在叶片头部采取ＳＰＨＧ１合金粉末喷焊材料一步法直接喷焊防护；②对叶片背面外缘强气蚀区和端面，在采用Ａ１３２焊条堆焊的基础上，采用ＳＰＨＧ１合金粉末喷焊材料两步法直接喷焊防护；③对叶片背面气蚀较轻部位和转轮体，用Ａ１３２焊条堆焊防护；④采用ＧＢ１焊条堆焊措施防护转轮室中环；⑤对叶片正面、导水叶、泄水锥及支持盖等部件可采用环氧金刚砂涂层防护。     

Analysis of the edge finite element approximation of the Maxwell equations with low regularity solutions

We derive $\mathit{H}$(curl)-error estimates and improved $\mathit{L}$²-error estimates for the Maxwell equations approximated using edge finite elements. These estimates only invoke the expected regularity pickup of the exact solution in the scale of the Sobolev spaces, which is typically lower than $\frac{1}{2}$ and can be arbitrarily close to $0$ when the material properties are heterogeneous. The key tools for the analysis are commuting quasi-interpolation operators in $\mathit{H}$(curl)- and $\mathit{H}$(div)-conforming finite element spaces and, most crucially, newly-devised quasi-interpolation operators delivering optimal estimates on the decay rate of the best-approximation error for functions with Sobolev smoothness index arbitrarily close to $0$. The proposed analysis entirely bypasses the technique known in the literature as the discrete compactness argument.     

Neighborhood-consensus message passing as a framework for generalized iterated conditional expectations

In this paper we propose a novel inference method for maximum a posteriori estimation with Markov random field prior. The central idea is to integrate a kind of joint “voting” of neighboring labels into a message passing scheme similar to loopy belief propagation (LBP). While the LBP operates with many pairwise interactions, we formulate “messages” sent from a neighborhood as a whole. Hence the name neighborhood-consensus message passing (NCMP). The practical algorithm is much simpler than LBP and combines the flexibility of iterated conditional modes (ICM) with some ideas of more general message passing. The proposed method is also a generalization of the iterated conditional expectations algorithm (ICE): we revisit ICE and redefine it in a message passing framework in a more general form. We also develop a simplified version of NCMP, called weighted iterated conditional modes (WICM), that is suitable for large neighborhoods. We verify the potentials of our methods on four different benchmarks, showing the improvement in quality and/or speed over related inference techniques.     

Implementation and performance of a parallel version of the HIRLAM limited area atmospheric model

The HIRLAM (high resolution limited area modelling) limited-area atmospheric model was originally developed and optimized for shared memory vector-based computers, and has been used for operational weather forecasting on such machines for several years. This paper describes the algorithms applied to obtain a highly parallel implementation of the model, suitable for distributed memory machines. The performance results presented indicate that the parallelization effort has been successful, and the Norwegian Meteorological Institute will run the parallel version in production on a Cray T3E.     

A Comparison of MPI,SHMEM and Cache-Coherent Shared Address Space Programming Models on a Tightly-Coupled Multiprocessors

We compare the performance of three major programming models on a modern, 64-processor hardware cache-coherent machine, one of the two major types of platforms upon which high-performance computing is converging. We focus on applications that are either regular, predictable or at least do not require fine-grained dynamic replication of irregularly accessed data. Within this class, we use programs with a range of important communication patterns. We examine whether the basic parallel algorithm and communication structuring approaches needed for best performance are similar or different among the models, whether some models have substantial performance advantages over others as problem size and number of processors change, what the sources of these performance differences are, where the programs spend their time, and whether substantial improvements can be obtained by modifying either the application programming interfaces or the implementations of the programming models on this type of tightly-coupled multiprocessor platform.